lib/access.c

   1 /* Test the access rights of a file.
   2    Copyright (C) 2019-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <unistd.h>
  21
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <string.h>
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27
  28 #if defined _WIN32 && !defined __CYGWIN__
  29 # include <io.h>
  30 #endif
  31
  32 int
  33 access (const char *file, int mode)
  34 #undef access
  35 {
  36   int ret;
  37
  38 #if defined _WIN32 && !defined __CYGWIN__
  39   if ((mode & X_OK) != 0)
  40     mode = (mode & ~X_OK) | R_OK;
  41   ret = _access (file, mode);
  42 #else
  43   ret = access (file, mode);
  44 #endif
  45
  46 #if (defined _WIN32 && !defined __CYGWIN__) || ACCESS_TRAILING_SLASH_BUG
  47 # if defined _WIN32 && !defined __CYGWIN__
  48   if (ret == 0 || errno == EINVAL)
  49 # else
  50   if (ret == 0)
  51 # endif
  52     {
  53       size_t file_len = strlen (file);
  54       if (file_len > 0 && file[file_len - 1] == '/')
  55         {
  56           struct stat st;
  57           if (stat (file, &st) == 0)
  58             {
  59               if (! S_ISDIR (st.st_mode))
  60                 {
  61                   errno = ENOTDIR;
  62                   return -1;
  63                 }
  64             }
  65           else
  66             return (mode == F_OK && errno == EOVERFLOW ? 0 : -1);
  67         }
  68     }
  69 #endif
  70   return ret;
  71 }